title: Transition from cold to hot thyroid nodules.
abstract: We report three cases of autonomously functioning thyroid nodules (AFTNs) that appeared hypofunctioning at radioactive iodine (131I) thyroid scan carried out at initial observation. Since at that time thyroid hormones and thyrotropin (TSH) were also normal, they were initially classified as "cold" nodules and treated with levothyroxine (LT4). The correct diagnosis of AFTN was made years later when a thyroid scintigraphy was repeated. In two of these patients, re-evaluation of the nodule was done because of the development of LT4 intolerance. A possible explanation is that these AFTNs had undergone hemorrhagic/cystic degeneration when they were first studied, but in subsequent years, proliferation of residual AFTN tissue caused the recurrence of a typical functioning nodule.
authors.affiliation: Istituto di Medicina Interna e Specialità Internistiche, Cattedra di Endocrinologia, Ospedale Garibaldi, University of Catania, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Tumino
authors.forename: C
authors.initials: C
authors.lastname: Fornito
authors.forename: A
authors.initials: A
authors.lastname: Laudani
authors.forename: M P
authors.initials: MP
authors.lastname: Iurato
authors.forename: A
authors.initials: A
authors.lastname: Belfiore
mesh_terms: D000328:Adult; D000075202:Contraindications; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D011877:Radionuclide Imaging; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000188:drug therapy; D013974:Thyroxine / Q000627:therapeutic use
chemical_list: D007457:Iodine Radioisotopes; D013974:Thyroxine